Production and characterization of high entropy alloy matrix composites

High entropy alloys are multicomponent alloy systems that have been researched by many researchers and scientists since their discovery. Thanks to their many excellent properties compared to conventional alloy systems, these alloys have developing rapidly. In this scope of the thesis, studies have been carried out on the evaluation of high entropy alloys as composite. CoCrFeNi based high entropy alloy as matrix phase and B4C and c-BN which are the two hardest ceramic phases were preferred as reinforcement phase. Composites were produced such that the proportion of reinforcement phases was 3%, 5%, 10% by weight. Powder metallurgy methods were used in the production of composite samples. Sintering process was carried out with Spark Plasma Sintering technique at 1000° C for c-BN reinforced composites and 900° C for B4C reinforced samples under 10 kN load. The effect of the phases and amount of reinforcement on composite properties such as condensation, microstructure development, elastic modulus, hardness and abrasion resistance were investigated. According to the results, it was determined that the hardness value and wear behavior improved as the reinforcement ratio increased. Boron and carbide phases were formed with the dissolution of B4C phase in the B4C reinforced samples and these new phases had a positive effect on hardness and abrasion.